Browse

You are looking at 121 - 130 of 91,274 items for

Open access

Nadeem ur Rehman, Radwan M. Al-omary and Najat Mohammed Muthana

Abstract

Let R be a prime ring with center Z(R). A map G : RR is called a multiplicative (generalized) (α, β)-derivation if G(xy)= G(x)α(y)+β(x)g(y) is fulfilled for all x; yR, where g : RR is any map (not necessarily derivation) and α; β : RR are automorphisms. Suppose that G and H are two multiplicative (generalized) (α, β)-derivations associated with the mappings g and h, respectively, on R and α, β are automorphisms of R. The main objective of the present paper is to investigate the following algebraic identities: (i) G(xy) + α(xy) = 0, (ii) G(xy) + α(yx) = 0, (iii) G(xy) + G(x)G(y) = 0, (iv) G(xy) = α(y) ○ H(x) and (v) G(xy) = [α(y), H(x)] for all x, y in an appropriate subset of R.

Open access

Nina Schuster and Anne Volkmann

Zusammenfassung

Um Lebenschancen räumlich differenziert zu erfassen, stellt unser Beitrag in Anknüpfung an die Quartierseffekteforschung und den „capability approach“ einen Ansatz vor, der Lebenschancen als räumlich strukturierte Möglichkeiten und Wahlfreiheiten bei der Erfüllung von Bedürfnissen konzipiert. Individuelle Ressourcen entscheiden darüber, welche Möglichkeitsräume der Bedürfnisbefriedigung erschlossen werden können. Dies ist abhängig von der Lebenslage und verändert sich im Lebensverlauf, womit sich auch die Rolle des Quartiers für die Lebenschancen ändert. Anstatt von „benachteiligenden Quartieren“ zu sprechen, fokussieren wir auf benachteiligende Lebenslagen im Quartier.

Open access

Imke Toborg

Abstract

If G is a finite group, then a bijective function f : GG is inverse ambiguous if and only if f(x)−1 = f −1(x) for all xG. We give a precise description when a finite group admits an inverse ambiguous function and when a finite group admits an inverse ambiguous automorphism.

Open access

Asiata Omotayo Ibrahim, Misbaudeen Abdul-Hammed, Samuel Adewale Adegboyega, Monsurat Olajide and Akeem Abefe Aliyu

Abstract

Tomato is a significant vegetable crop with numerous health benefits derived from its carotenoids, flavonoids and other phytonutrients contents. This work studies the nutritional qualities and carotenoids contents of five different cultivars of tomatoes (San Marz, Nasmata, Roma VF, Ogbomoso local and 4-lobes). The variations of pH, titratable acidity, reducing sugar, total solid, lycopene and beta-carotene contents of these tomatoes were investigated under ambient temperature and field ripening techniques and the mean values of these parameters investigated at different ripening stages and techniques were compared. Lycopene contents were significantly higher (p ˂ 0.05) in tomatoes subjected to field ripening compared with those ripened under ambient temperature. The highest lycopene content (17.18 μg/g) was observed in Roma VF cultivar at fully-ripe stage under field ripening technique while the lowest value (0.64 μg/g) was in 4-lobes cultivar at semi-ripe stage under ambient temperature ripening. Similar trend was observed in the variation of betacarotene (a pro-Vitamin A index) among the tomato cultivars. The evaluated reducing sugar contents (ranging from 1.84 to 5.23 μg/g) were significantly higher (p < 0.05) in fully-ripe tomatoes compared to semi-ripe ones under field ripening and the trend was reversed for some cultivars under ambient temperature ripening. The titratable acidities of the tomatoes were significantly higher at the semi-ripe stage (0.24 to 0.38 %) under field ripening than those obtained under ambient temperature ripening (0.15 to 0.25 %). The pH of the tomatoes ranged from 3.58 to 4.07 and 3.46 to 5.40 under field and ambient temperature ripening, respectively, and the higher pH values obtained under ambient temperature ripening condition could make such tomatoes unsuitable in tomato processing plants. Consumption of tomatoes for the purpose of dietary antioxidant lycopene and pro-Vitamin A could maximally be achieved at fully-ripe stage under field ripening condition.

Open access

Minodora Onisâi, Ana-Maria Vlădăreanu, Andreea Spînu, Mihaela Găman and Horia Bumbea

Abstract

Immune thrombocytopenia is an autoimmune hematological disorder characterized by severely decreased platelet count of peripheral cause: platelet destruction via antiplatelet antibodies which may also affect marrow megakaryocytes. Patients may present in critical situations, with cutaneous and/or mucous bleeding and possibly life-threatening organ hemorrhages (cerebral, digestive, etc.) Therefore, rapid diagnosis and therapeutic intervention are mandatory.

Corticotherapy represents the first treatment option, but as in any autoimmune disorder, there is a high risk of relapse. Second line therapy options include: intravenous immunoglobulins, thrombopoietin receptor agonists, rituximab or immunosuppression, but their benefit is usually temporary. Moreover, the disease generally affects young people who need repeated and prolonged treatment and hospitalization and therefore, it is preferred to choose a long term effect therapy. Splenectomy – removal of the site of platelet destruction – represents an effective and stable treatment, with 70-80% response rate and low complications incidence.

A challenging situation is the association of ITP with pregnancy, which further increases the risk due to the immunodeficiency of pregnancy, major dangers of bleeding, vital risks for mother and fetus, potential risks of medication, necessity of prompt intervention in the setting of specific obstetrical situations – delivery, pregnancy loss, obstetrical complications, etc.

We present an updated review of the current clinical and laboratory data, as well as a detailed analysis of the available therapeutic options with their benefits and risks, and also particular associations (pregnancy, relapsed and refractory disease, emergency treatment).

Open access

W.C. Shen, L.L. Lin, C.Y. Shen, S. Xing and Z.B. Pan

Abstract

TbxHo0.9−xNd0.1(Fe0.8Co0.2)1.93/epoxy (0 ⩽ x ⩽ 0.40) composites are fabricated in the presence of a magnetic field. The structural and dynamic magnetoelastic properties are investigated as a function of both magnetic bias field Hbias and frequency f at room temperature. The composites are formed as textured orientation structure of 1–3 type with 〈1 0 0〉 preferred orientation for x ⩽ 0.10 and 〈1 1 1〉-orientation for x ⩾ 0.25. The composites generally possess insignificant eddy-current losses for frequency up to 50 kHz, and their dynamic magnetoelastic properties depend greatly on Hbias. The elastic modulus (E3H and E3B) shows a maximum negative ΔE effect, along with a maximum d33, at a relatively low Hbias ~ 80 kA/m, contributed by the maximum motion of non-180° domain-wall. The 1–3 type composite for x ⩾ 0.25 shows an enhanced magnetoelastic effect in comparison with 0 to 3 type one, which can be principally ascribed to its easy magnetization direction (EMD) towards 〈1 1 1〉 axis and the formation of 〈1 1 1〉-texture-oriented structure in the composite. These attractive dynamic magnetoelastic properties, e.g., the low magnetic anisotropy and d33,max as high as 2.0 nm/A at a low Hbias ~ 80 kA/m, along with the light rare-earth Nd element existing in insulating polymer matrix, would make it a promising magnetostrictive material system.

Open access

Denis Sokol, Maksim Ivanov, Andrei N. Salak, Robertas Grigalaitis, Juras Banys and Aivaras Kareiva

Abstract

Magnesium-aluminum-bismuth layered double hydroxides (Mg3Al1−xBix; LDHs) were prepared using both coprecipitation and sol-gel methods. For the preparation of Mg/Al/Bi LDH by the co-precipitation method, the appropriate amounts of dissolved starting materials (Al(NO3)3 · 9H2O, Mg(NO3)2 · 6H2O and Bi(NO3)3 · 5H2O) were mixed with a solution of NaHCO3:NaOH. In the sol-gel processing, the precursor Mg–Al–Bi–O gels were synthesized using the same starting materials and ethylene glycol as complexing agent. The mixed-metal oxides obtained by subsequent heating of Mg–Al–Bi–O gels at 650 °C were reconstructed to Mg3Al1−xBix LDHs in water at 80 °C. All the synthesized products were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and dielectric measurements.

Open access

Rafał Mazur, Sebastian Masternak, Michał Pająk, Nikodem Skoczeń, Ewelina Soroka and Marcin Olajossy

Abstract

Introduction: Smoking is a huge medical and social problem in Poland, with as many as about 24% of Poles being addicted to nicotine. Approximately 6 million people worldwide die every year from conditions that are closely related to tobacco addiction, such as cancer and cardiovascular, metabolic or lung diseases. The difficulty in combatting nicotine dependence is largely due to the complex mechanism of this addiction. The motivation of a patient to quit smoking is of great importance in the difficult withdrawal process. Strengthening this motivation is one of the most important tasks of physicians and addiction therapists.

Overview of literature: Nicotine replacement therapy (NRT) has been the most widely known way to break away from smoking addiction for many years now. It involves delivering nicotine to the body in ways that are less harmful than through tobacco smoke. As a consequence, the cravings for nicotine are reduced, making it easier for the patient to break with the addiction. Clinical trials have shown that the use of NRT is associated with a 50-70% increased chance of maintaining abstinence from smoking compared to placebo. There are many NRT products, including nicotine chewing gum, nicotine patches, lozenges, dissolvable nicotine sticks, or inhalers. Bupropion is a selective dopamine–noradrenaline reuptake inhibitor. This drug is one of the most commonly used in the pharmacotherapy of depression in the United States. At the same time, it has been found to have a positive effect on people trying to break up with the habit of smoking cigarettes. The mechanism of action remains unknown in this case, but studies clearly indicate the efficacy of bupropion, which is comparable to the efficacy of NRT. Varenicline is a partial agonist selective for α4β2 nicotinic acetylcholine receptors. It has a higher affinity for these receptors than nicotine. By stimulating them, it causes an increase in dopamine secretion (but to a lesser extent than cigarette smoking), helping in this way ease withdrawal symptoms.

Conclusions: Varenicline has higher efficacy than bupropion and NRTs. Simultaneous use of two NRT forms increases the effectiveness of this method to a level comparable to varenicline. Contrary to previous reports, it seems that varenicline does not increase self-aggressive behaviour and the risk of suicide. The effectiveness of antinicotinic drugs depends on the sex of the patient. For both sexes, the most effective drug is varenicline. It is slightly more effective in women than in men. By contrast, NRT and bupropion show greater therapeutic potential in men.

Open access

Mohammad Abu Haija, Georgia Basina, Fawzi Banat and Ahmad I. Ayesh

Abstract

Spinel ferrite nanoparticles in the form CuFe2O4 were tested for gas sensing applications. Nanoparticles pressed in a disk form were used to construct conductometric gas sensors. The disk was placed between two electrical electrodes wherein the top electrode had a grid structure. The produced sensors were tested against H2S and H2 gases and they were found to be selective and sensitive to H2S concentration as low as 25 ppm. The composition of the nanoparticles was confirmed by X-ray diffraction and energy dispersive X-ray spectroscopy measurements. The crystal structure was verified by both X-ray diffraction and transmission electron microscope. The observations obtained from the experiments demonstrated the high potential of using CuFe2O4 nanoparticles for H2S sensing applications.

Open access

Darja Kanduc

Abstract

This study investigates the hypothesis that cross-reactions may occur between human cardiac proteins and influenza antigens, thus possibly representing the molecular mechanism underlying influenzaassociated sudden unexpected death (SUD). Using titin protein as a research model, data were obtained on (1) the occurrence of the titin octapeptide AELLVLLE or its mimic AELLVALE in influenza A virus hemagglutinin (HA) sequences; (2) the immunological potential of AELLVLLE and its mimic AELLVALE; (3) the possible role of the flanking amino acid aa) context of the two octapeptide determinants in eliciting cross-reactivity between the human cardiac titin protein and HA antigens.